Endotracheal tube having outer and inner cannulae

ABSTRACT

A tracheal tube apparatus includes a cannula having first and second ends. An inflatable cuff is formed on the cannula between the first and second ends. A conduit extends from the cuff for introducing an inflating fluid into the cuff when it is desired to inflate the cuff and removing inflating fluid from the cuff when it is desired to deflate the cuff. A gauge for indicating the inflation pressure of the cuff is coupled in the conduit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Ser. No. 15/443,072, which wasfiled on Feb. 27, 2017, which claimed priority to U.S. Ser. No.14/728,540, now U.S. Pat. No. 9,579,477, which was filed on Jun. 2, 2015and claimed priority to U.S. Ser. No. 62/135,231 filed Mar. 19, 2015,and International Application No. PCT/US2013/072237 filed Nov. 27, 2013,which claimed priority to U.S. Ser. No. 13/691,924 filed Dec. 3, 2012,now U.S. Pat. No. 8,707,956, which is a continuation-in-part of U.S.Ser. No. 12/885,644 filed Sep. 20, 2010. U.S. Ser. No. 12/885,644 isitself a divisional of U.S. Ser. No. 11/318,649 filed Dec. 27, 2005, nowU.S. Pat. No. 7,987,851. The disclosures of U.S. Ser. No. 15/443,072;U.S. Pat. No. 9,579,47, U.S. Ser. No. 62/135,231, InternationalApplication No. PCT/US2013/072237, U.S. Pat. No. 8,707,956, U.S. Pat.No. 7,987,851, and U.S. Ser. No. 12/885,644, are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to endotracheal tubes such as, forexample, orotracheal tubes and nasotracheal tubes.

BACKGROUND

A tracheal tube is typically a catheter that is inserted into thetrachea for the purpose of providing an airway for a patient. Anendotracheal tube is a specific type of tracheal tube that is insertedthrough the mouth (orotracheal) or nose (nasotracheal). Suchendotracheal tubes are in contrast to a tracheostomy tube, which isinserted into a tracheostoma following a tracheostomy procedure, and atracheal button, which may also be inserted into a puncture through theparatracheal skin into the trachea.

An endotracheal tube may be cuffed or uncuffed. Cuffed endotrachealtubes include a cuff that can be inflated to minimize the passage ofsecretions from the upper respiratory tract downward into the lungs of apatient. One problem with cuffed endotracheal tubes is the pooling ofsaliva and other secretions around the inflated cuff and the potentialfor such secretions to leak past the cuff and into the lungs.

The following are of interest: U.S. Pat. Nos.: 1,598,283; 2,892,458;3,688,774; 3,996,939; 4,211,234; 4,223,411; 4,280,492; 4,304,228;4,305,392; 4,315,505; 4,327,721; 4,449,523; 4,459,984; 4,469,100;4,573,460; 4,584,998; 4,589,410; 4,596,248; 4,607,635; 4,627,433;4,632,108; 4,637,389; 4,762,125; 4,834,087; 4,840,173; 4,852,565;5,056,515; 5,067,497; 5,107,828; 5,123,922; 5,201,310; 5,217,008;5,218,970; 5,255,676; 5,297,546; 5,329,921; 5,339,808; 5,343,857;5,349,950; 5,391,205; 5,392,775; 5,458,139; 5,497,768; 5,507,279;5,515,844; 5,584,288; 5,599,333; RE 35,595; 5,687,767; 5,688,256;5,746,199; 5,771,888; 5,957,978; 6,053,167; 6,089,225; 6,102,038;6,105,577; 6,135,110; 6,135,111; 6,463,927; 6,722,367; 6,814,007;7,404,329 ; U.S. patent publications: 2003/0084905; 2004/0123868;foreign/international patent publications: DE 25 05 123; DE 34 06 294;DE 37 20 482; DE 38 13 705; DE 195 13 831; DE 101 09 935; WO 99/07428;WO 99/12599; WO 00/32262; other publications: Quick Reference Guide toShiley's “Quality-Of Life” Line of Tracheostomy Products, 1991;Granuloma Associated with Fenestrated Tracheostomy Tubes, PadmanabhanSiddharth, MD, PhD, FACS and Lawrence Mazzarella, MD, FACS, CaseReports, vol. 150, Aug. 1985, pp. 279-280; Technical Support InformationConnections with the Passy-Muir Tracheostomy and Ventilator SpeakingValves, one sheet; Tracheostomy and Laryngectomy Tubes, pp. 568 and 572;Tracheostomy Tube Adult Home Care Guide, Shiley Tracheostomy Products,Mallinckrodt Medical pp. 1-40; D. Hessler, MD, K. Rehder, MD and S. W.Karveth, MD, “Tracheostomy Cannula for Speaking During ArtificialRespiration”, Anesthesiology, vol. 25, No. 5, pp. 719-721 (1964). Norepresentation is intended by this listing that a thorough search of allmaterial prior art has been conducted, or that no better art than thatlisted is available. Nor should any such representation be inferred. Thedisclosures of all of the above are hereby incorporated herein byreference.

SUMMARY

According to an aspect, an endotracheal tube apparatus includes an outercannula having first and second ends. A fenestration is provided alongthe length of the outer cannula between the first and second ends. Aninflatable cuff is formed on the outer cannula between the fenestrationand the second end. A first conduit extends from the cuff forintroducing an inflating fluid into the cuff when it is desired toinflate the cuff and removing inflating fluid from the cuff when it isdesired to deflate the cuff. An inner cannula is sized selectively to beinserted into, and removed from, the outer cannula. The inner cannulaincludes a second conduit to evacuate a region of a trachea of a weareradjacent the cuff. The second conduit includes an opening which liesadjacent the closest point in the fenestration to the cuff when theinner cannula is selectively inserted into a use orientation in theouter cannula.

Illustratively, the apparatus further includes a gauge coupled in thefirst conduit for indicating the inflation pressure of the cuff.

Illustratively, the apparatus further includes a one-way valve at an endof the first conduit remote from the cuff for preventing escape ofinflating fluid from the cuff.

Illustratively, the cuff comprises a sleeve including a first end, asecond end, and a third region between the first and second ends. Thesleeve is located around the outer cannula with at least the first endof the sleeve between the outer cannula and the third region of thesleeve.

Illustratively, the first and second ends of the sleeve are both betweenthe outer cannula and the third region of the sleeve.

Illustratively, the apparatus further comprises a first coupler providedon an outer end of the outer cannula and a second coupler provided on anouter end of the inner cannula. Each of the first and second couplers isprovided with at least one cooperating surface for guiding the innercannula into a predetermined orientation with respect to the outercannula when the inner cannula is inserted into the outer cannula.

Illustratively, the apparatus further comprises at least one tabprovided on an outer end of one of the outer cannula and the innercannula. The at least one tab includes an engaging surface. At least onecoupler is provided on an outer end of the other one of the outercannula and the inner cannula for engagement by the at least one tab.The at least one coupler includes a portion for cooperating with theengaging surface for orienting the inner cannula in a predeterminedorientation with respect to the outer cannula.

Illustratively, the at least one tab is flexibly formed or mounted tosaid one of the outer cannula and the inner cannula.

According to another aspect, a tracheal tube apparatus includes acannula having first and second ends. An inflatable cuff is formed onthe cannula between the first and second ends. A conduit extends fromthe cuff for introducing an inflating fluid into the cuff when it isdesired to inflate the cuff and removing inflating fluid from the cuffwhen it is desired to deflate the cuff. A gauge is coupled to theconduit for indicating the inflation pressure of the cuff.

Illustratively, the apparatus further includes a one-way valve at an endof the conduit remote from the cuff. The one-way valve prevents escapeof inflating fluid from the cuff.

Illustratively, the cuff comprises a sleeve including a first end, asecond end, and a third region between the first and second ends. Thesleeve is located around the cannula with at least the first end of thesleeve between the cannula and the third region of the sleeve.

Illustratively, the first end of the sleeve and the second end of thesleeve are both between the cannula and the third region of the sleeve.

According to another aspect, an endotracheal tube apparatus isdisclosed. The endotracheal tube comprises an outer cannula having afirst longitudinal end and a second longitudinal end. The outer cannulahas an outer surface that is devoid of openings between the firstlongitudinal end and the second longitudinal end. The endotracheal tubealso comprises an inner cannula sized to be selectively inserted into,and removed from, the outer cannula. The inner cannula has a firstlongitudinal end, a second longitudinal end, and an outer surface thatis devoid of openings between the first longitudinal end and the secondlongitudinal end.

In some embodiments, the endotracheal tube apparatus may furthercomprise an inflatable cuff formed on the outer cannula between itsfirst and second longitudinal ends.

In some embodiments, the endotracheal tube apparatus may furthercomprise a conduit extending from the cuff for introducing fluid intothe cuff when it is desired to inflate the cuff and removing fluid fromthe cuff when it is desired to deflate the cuff.

Additionally, in some embodiments, the endotracheal tube apparatus mayfurther comprise a first coupler provided on the second longitudinal endof the outer cannula and a second coupler provided on the secondlongitudinal end of the inner cannula. One of the first and secondcouplers may be provided with at least one surface for guiding the innercannula into the use orientation with respect to the outer cannula whenthe inner cannula is inserted into the outer cannula, and the other ofthe first and second couplers may be provided with a cooperating surfacefor cooperating with the at least one surface for guiding the innercannula into the use orientation with respect to the outer cannula.

According to another aspect, a method of using an endotracheal tubeapparatus is disclosed. The method comprises inserting an endotrachealtube orally or nasally into a trachea of a patient. The endotrachealtube comprises an outer cannula having a first longitudinal end, asecond longitudinal end, and an outer surface that is devoid of openingsbetween the first longitudinal end and the second longitudinal end. Themethod also comprises removing an inner cannula from the outer cannula.The inner cannula has a first longitudinal end, a second longitudinalend, and an outer surface that is devoid of openings between the firstlongitudinal end and the second longitudinal end. The method furthercomprises maintaining the outer cannula in the trachea of the patientand inserting the inner cannula into the outer cannula with the outercannula in the trachea of the patient.

In some embodiments, the method may further comprise inflating a cuffformed on the outer cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdetailed description and accompanying drawings which illustrate theinvention. In the drawings:

FIG. 1 illustrates a fragmentary perspective view of a system accordingto the invention in a disassembled configuration;

FIG. 1a illustrates a longitudinal sectional side elevational view ofthe anatomy of the upper airway of a wearer with the apparatusillustrated in FIG. 1 in place;

FIG. 2 illustrates a perspective view of a portion of the systemillustrated in FIG. 1;

FIG. 3 illustrates a perspective view of a portion of the systemillustrated in FIG. 1;

FIG. 4 illustrates an enlarged longitudinal sectional side elevationalview of a detail of FIGS. 1 and 3, taken generally along section lines4-4 of FIG. 3;

FIG. 5 illustrates an enlarged longitudinal sectional side elevationalview of a detail of FIGS. 1 and 2, taken generally along section lines5-5 of FIG. 2;

FIG. 5a illustrates an enlarged longitudinal sectional side elevationalview of an alternative detail to the detail illustrated in FIG. 5;

FIGS. 6a-c illustrate enlarged front elevational, side elevational andrear elevational views, respectively, of a detail of FIGS. 1 and 2;

FIGS. 7a-e illustrate schematic circuit diagrams of the detailillustrated in FIGS. 6a -c;

FIG. 8 illustrates a perspective view of another endotracheal tubeincluding inner and outer cannulae; and

FIG. 9 is a longitudinal sectional side elevation view illustrating theendotracheal tube of FIG. 8 inserted into an upper airway of a patient.

DETAILED DESCRIPTIONS OF ILLUSTRATIVE EMBODIMENTS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been illustrated by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Referring now particularly to FIGS. 1 and 1 a, an endotracheal tubesystem 10, here an orotracheal tube system, includes an outer cannula 12for insertion through the mouth of a wearer 20, down the wearer 20'spharynx 24, through the wearer 20's glottis 22 and into the wearer 20'strachea 18. Outer cannula 12 includes an inflatable cuff 16. Cuff 16lies in the trachea 18 of the wearer 20 below the wearer 20's glottis22. Outer cannula 12 also includes a first port 26 which resides outsidethe mouth of the wearer 20 during use and a second port 28 which residesinside the trachea 18 of the wearer 20 below cuff 16 during use. Thecuff 16 is inflatable through a conduit 30 once the outer cannula 12 isin place in the trachea 18 to minimize the passage of secretions 32 fromthe upper respiratory tract downward into the lungs of the wearer 20.Such secretions 32 pool above the cuff 16 (that is, on the side of thecuff 16 opposite the lungs) when the cuff 16 is inflated in place. Theconstruction of the cuff 16 as a sleeve 42, FIG. 5, with its upper andlower ends 44, 46, respectively, tucked under, rather than extendingbeyond the cuff 16 up and down the outer sidewall of the outer cannula12, is aided by the use of thin-walled material for the cuff 16. In analternative embodiment, illustrated in FIG. 5a , only upper end 44′ istucked under, rather than extending beyond the cuff 16 up the outersidewall of the outer cannula 12′. The constructions illustrated inFIGS. 5 and 5 a provide certain benefits which will be discussedsubsequently.

The outer cannula 12 includes (a) fenestration(s) 56. Although two suchfenestrations 56 are illustrated, it should be understood that anynumber of fenestrations 56 may be provided in the outer cannula 12 forthis purpose. The construction of cuff 16, with its doubled-over upperand lower ends 44, 46, respectively, (FIG. 5) or doubled-over upper end44′ (FIG. 5a ), permits location of the fenestration(s) 56 low (that is,more toward the lungs of the wearer 20) on the outer cannula 12. Theproximity of the cuff 16 to the fenestration(s) 56 also provides someadditional protection of the tissue of the trachea 18 against irritationand damage occasioned by contact with the edges of the fenestration(s)56 by virtue of the standoff provided by the inflated cuff 16.

Referring now particularly to FIGS. 1 and 3, an inner cannula 60 isinserted into the lumen 62 of the outer cannula 12. To evacuate poolingsecretions 32, a conduit 70 extends down the sidewall of inner cannula60. Conduit 70 terminates at an open end 72 at the bottommost extent offenestrations 56 to expose the secretions 32 to suction at open end 72of tube 70 provided by a suction source 73 at the outer end of innercannula 60. Owing to the construction of cuff 16 with its doubled-underend 44, this location generally coincides with the top of the cuff 16 atthe bottommost extent of fenestration 56. Owing to this construction,extraction of secretions 32 is somewhat more predicable and complete.

In addition, it is contemplated that replacement of the inner cannula 60may occur more frequently and with less difficulty and without much ofthe trauma that might attend replacement of outer cannula 12, which istypically placed in the trachea for a longer term. Typically, both theouter 12 and inner cannulae 60 are constructed from suitable filledand/or unfilled resin(s) and/or polymer(s). Inner cannula 60 typicallycan be relatively straightforwardly replaced by disconnecting it fromthe ventilator 74 (illustrated diagrammatically) to which the outer end76 of inner cannula 60 is attached in use and withdrawing inner cannula60 from outer cannula 12. Because of the relative ease with which innercannula 60 can be removed, disposed of if appropriate, and replaced witha fresh cannula 60 having a fresh tube 70, providing tube 70 on innercannula 60 rather than on outer cannula 12 affords somewhat morereliable patency of tube 70 than if the tube 70 were to be provided inouter cannula 12 which, as noted above, is typically not so readilyremoved for cleaning or replacement.

Referring now to FIG. 1, the inner cannula 60 is releasably fixed to anouter cannula 12 by one or more (two in the illustrated embodiment)locking tabs 100 which may be formed with, and from the same materialas, the coupler 76 of cannula 60 by which cannula 60 is coupled to theventilator 74. The tabs 100 are flexibly formed or mounted to thecoupler 76 of inner cannula 60. The tabs 100 are provided with engagingsurfaces 106. A coupler 108 is provided at the proximal end 54 of outercannula 12. The coupler 108 includes a notch 114 for receiving theportion of each tab 100 which extends beyond engaging surfaces 106 andportions 116 for capturing engaging surfaces 106. This configurationalso promotes correct orientation of inner cannula 60 with thefenestration(s) (56 in FIG. 1) of outer cannula 12 when inner cannula 60is inserted into outer cannula 12.

Referring to FIGS. 1 and 2, a digital pressure gauge 304 is insertedinto the conduit 30 between a fitting 302 and cuff 16 by a fitting 306provided on gauge 304. Fitting 302 is configured complementarily to afitting on a source 307 of compressed air, such as a syringe. Such afitting might be, for example, a Luer lock fitting or other suitablefitting to couple the compressed air source to fitting 302 for thispurpose. Fitting 302 may also include a one-way valve of a suitabletype, such as, for example, a ball valve, to prevent the escape of cuff16-inflating air, permitting the compressed air source 307 to bedisconnected from fitting 302 once cuff 16 is inflated to a suitablepressure.

The schematic and block circuit diagram descriptions that followidentify specific integrated circuits and other components and in manycases specific sources for these. Specific terminal and pin names andnumbers are generally given in connection with these for the purposes ofcompleteness. It is to be understood that these terminal and pinidentifiers are provided for these specifically identified components.It is to be understood that this does not constitute a representation,nor should any such representation be inferred, that the specificcomponents, component values or sources are the only componentsavailable from the same or any other sources capable of performing thenecessary functions. It is further to be understood that other suitablecomponents available from the same or different sources may not use thesame terminal/pin identifiers as those provided in this description.

The gauge 304 removed from its housing 305 is illustrated in FIGS. 6a-c. An electrical schematic of gauge 304 is illustrated in FIGS. 7a-e . Asillustrated in FIGS. 1, 2, 6 a, 6 b and 7 a, gauge 304 includes a twodigit (seven segments each) liquid crystal display (LCD) 310 whichillustratively is a Glory Sound (Asia) Ltd., AE359 type DS-M2684-Fdisplay. Referring to FIGS. 6b and 7b , the driver 312 for display 310illustratively is a Freescale Semiconductor MC9S08QB4QFN microcontroller(μC). Pins 1-4, the Vdd, Vrefh, Vrefl and Vss terminals, respectively,of driver 312 are coupled to the gauge 304's+Vbat, +Vbat, common andcommon terminals, respectively. Vrefh is coupled to+Vbat through a 1.8μH inductor. +Vbat and common are the+and−terminals, respectively, of,for example, a 3V lithium PC 2 pin mount, 170 mAh coin cell 313 such as,for example, a Renata SA type 614-CR2025FH-MFR-LF coin cell. See FIGS.6a -c.

Referring again to FIG. 7b , the parallel combination of a 2.2 μFcapacitor and a 100 nF capacitor is coupled across pins 1 and 4 of μC312. The parallel combination of a 2.2 F capacitor and a 100 nFcapacitor is coupled across pins 2 and 3. Pins 5-24, terminals PB7/EXTL,PB6/XTL, PBS, PB4, PC1, PC0, PB3/AD7, PB2/AD6, PB1/TXD/ADS, PB0/RXD/AD4,PA7, PA6, PA3/AD3, PA2/AD2, PA1/ADL PA0/AD0, PC7, PC6, PA5/*RST, andPA4/BKGD, respectively, of driver 312 are coupled to LCD COM, LCDsegment 1G, LCD segment 1F, LCD segment 1E, LCD segment 2B, LCD segment2A, LCD segment 1D, LCD segment 1C, LCD segment 1B, LCD segment 1A, LCDsegment 2G, LCD segment 2F, LCD segment 2E, not connected, the gauge304's TEMPerature terminal, the gauge 304's NET_PRESSure terminal, LCDsegment 2D, LCD segment 2C, through a 100 nF capacitor to gauge 304'scommon terminal, and through a 4.7 KΩ resistor to+Vbat. Another 4.7 KΩresistor is coupled between pin 23 of driver 312 and+Vbat.

Referring to FIGS. 6b, 6c and 7c , pressure at port 306, which is thecuff 16 inflation pressure, is monitored by a pressure sensor 320,illustratively a Freescale Semiconductor type MPX10 or MPX12uncompensated silicon pressure sensor. Sensor 320 pins 1-4 are coupledrespectively to the gauge 304 common, through a 10 KΩ resistor to thenon-inverting (+) input terminal, pin 3, of a differential amplifier322, to gauge 304's+Vbat terminal, and through a 10 KΩ resistor toamplifier 322's inverting (−) input terminal, pin 2 Amplifier 322illustratively is one-fourth of a National Semiconductor type LMC6464AIMquad differential amplifier. Feedback is provided from the outputterminal, pin 1, of amplifier 322 to the−input terminal of amplifier 322through a 100 KΩ resistor. Pin 4 of amplifier 322 is coupled to+Vbat.Pin 11 of amplifier 322 is coupled to common. The parallel combinationof a 2.2 μF capacitor and a 100 nF capacitor is coupled across+Vbat andcommon. Pin 1 of amplifier 322 is coupled to a+terminal, pin 5 of adifferential amplifier 324. An output terminal, pin 7, of amplifier 324is coupled to amplifier 324's−input terminal, pin 6, configuringamplifier 324 as a unity gain buffer. Pin 7 of amplifier 324 forms thegauge 304's NET_PRESSure terminal Amplifier 324 illustratively isone-fourth of a National Semiconductor type LMC6464AIM quad differentialamplifier.

Referring to FIG. 7d , a 10 KΩ, 1% thermistor 330, such as a Vishay type71-TFPT1206L1002FV thermistor, and a 10 KΩ, 1% resistor are coupled inseries between+Vbat and common. The common terminal of thermistor 330and the 10 KΩ resistor is coupled to the+input terminal, pin 12, of adifferential amplifier 332. An output terminal, pin 14, of amplifier 332is coupled to amplifier 332's−input terminal, pin 13, configuringamplifier 332 as a unity gain buffer. Pin 14 of amplifier 332 forms thegauge 304's TEMPerature terminal Amplifier 332 illustratively isone-fourth of a National Semiconductor type LMC6464AIM quad differentialamplifier. Referring to FIGS. 6a, 6b and 7e , +Vbat is supplied to theillustrated circuitry through a suitable switch 334, such as a Snaptrondome switch.

The topography of gauge 304 can best be understood by referring to FIGS.6a-c , where the relative locations of fitting 306, LCD 310, driver 312,battery 313, pressure sensor 320 and switch 334 can be readilyascertained. Gauge 304 is configured to be reliable yet inexpensive inkeeping with the philosophy that inner cannula 60 be rendereddisposable. However, gauge 304 can be provided with a T-junction andconduit 30 and fitting 302 with appropriate complementary fittings, sothat the T-junction can readily be disconnected from and reconnectedinto the conduit 30 between cuff 16 and fitting 302, should it beappropriate to retain the gauge 304 and dispose of the inner cannula 60.In such embodiments, gauge 304 could be reused as long as it remainedoperable.

Referring now to FIG. 8, an endotracheal tube apparatus 410 is shown. Inthe illustrative embodiment, the endotracheal tube apparatus is anorotracheal apparatus configured for insertion through a patient's mouthand into his or her trachea. In other embodiments, the endotracheal tubeapparatus may be a nasotracheal apparatus configured for insertionthrough a patient's nose. The apparatus 410 includes an outer cannula412 and an inner cannula 414 sized to be selectively inserted into, andremoved from, the outer cannula 412. The cannulae 412, 414 are formed ascomponents from polyvinyl chloride but may also be formed from siliconeor other suitable biocompatible material(s).

The outer cannula 412 has a distal longitudinal end 416 and a proximallongitudinal end 418. A passageway or lumen 420 extends through ports422, 424 defined in the ends 416, 418, respectively. The cannula 412also has an outer surface 426 that extends between the ends 416, 418. Asshown in FIG. 8, the outer surface 426 is devoid of any fenestrations orother openings. In the illustrative embodiment, an inflatable cuff 428is provided on the outer surface 426 between the ends 416, 18. The cuff428 is inflatable through a conduit 430 once the outer cannula 412 is inplace in the trachea, as described in greater detail below.

The inner cannula 414 is sized to be inserted into the lumen 420 of theouter cannula 412. The inner cannula 414 has a distal longitudinal end436 and a proximal longitudinal end 438. A passageway or lumen 440extends through ports 442, 444 defined in the ends 436, 438,respectively. The cannula 414 also has an outer surface 46 that extendsbetween the ends 436, 438. As shown in FIG. 8, the outer surface 446 isdevoid of any openings. In the illustrative embodiment, the innercannula 414 may be coupled to a ventilator (not shown).

The inner cannula 414 is releasably fixed to an outer cannula 412 via anattachment mechanism 448. In the illustrative embodiment, the attachmentmechanism 448 includes one or more (two in the illustrated embodiment)couplers or locking tabs 450 that are flexibly formed or mounted to theproximal longitudinal end 438 of the inner cannula 414. The tabs 450 areprovided with engaging surfaces 452. The attachment mechanism 448 alsoincludes a coupler 454 at the proximal longitudinal end 418 of the outercannula 412. The coupler 454 includes a notch 456 for receiving theportion of each tab 450 which extends beyond engaging surfaces 452 andportions 458 for capturing engaging surfaces 452. This configurationalso promotes correct orientation of inner cannula 414 within outercannula 412.

In use, the endotracheal tube apparatus 410 is inserted through apatient's mouth 470, down the patient's pharynx 472, through thepatient's glottis 474, and into the patient's trachea 476, as shown inFIG. 9. The port 424 at the proximal longitudinal end 418 of the outercannula 412 is positioned outside the patient's mouth 470 during use andthe port 422 at the distal longitudinal end 16 of the outer cannula 412is positioned inside the trachea 476 below cuff 428 during use. Asdescribed above, the cuff 428 is inflatable through a conduit 30 oncethe outer cannula 412 is in place in the trachea 476 to minimize thepassage of secretions 480 from the upper respiratory tract downward intothe patient's lungs. Such secretions 480 pool above the cuff 428 (thatis, on the side of the cuff 428 opposite the lungs) when the cuff 428 isinflated in place.

As described above, the inner cannula 414 may be removed from the outercannula 412. It is contemplated that replacement of the inner cannula414 may occur more frequently and with less difficulty and without muchof the trauma that might attend replacement of the outer cannula 412,which is typically placed in the trachea for a longer term. The innercannula 414 typically can be relatively straightforwardly replaced bydisconnecting it from the ventilator (if any), releasing the coupler(s)450 and withdrawing the inner cannula 414 from the outer cannula 412.The inner cannula 414 thus can be removed, disposed of if appropriate,and replaced with a fresh cannula 414 with relative ease.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such illustration and description isto be considered as exemplary and not restrictive in character, it beingunderstood that only illustrative embodiments have been illustrated anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. (canceled)
 2. An endotracheal tube apparatus comprising: an outercannula configured for insertion through a mouth of a wearer, down apharynx of the wearer, through a glottis of the wearer, and into atrachea of the wearer, the outer cannula including a fenestration alonga length of the outer cannula, an inflatable cuff formed on the outercannula adjacent to the fenestration and the second end, a first conduitextending from the cuff for introducing an inflating fluid into the cuffwhen it is desired to inflate the cuff and removing inflating fluid fromthe cuff when it is desired to deflate the cuff, and a plurality ofinner cannulas sized to be selectively and separately inserted into, andremoved from, the outer cannula, wherein the plurality of inner cannulasinclude a first inner cannula including a first and second lumen, thesecond lumen configured to evacuate a region of the trachea of thewearer adjacent the cuff, the second lumen including an opening whichlies adjacent the closest point in the fenestration to the cuff when thefirst inner cannula is selectively inserted into a use orientation inthe outer cannula.
 3. The apparatus of claim 2, further comprising agauge for indicating an inflation pressure of the cuff, the gaugecoupled in the first conduit.
 4. The apparatus of claim 3, furthercomprising a one-way valve at an end of the first conduit remote fromthe cuff, the one-way valve preventing escape of inflating fluid fromthe cuff.
 5. The apparatus of claim 2, further comprising a one-wayvalve at an end of the first conduit remote from the cuff, the one-wayvalve preventing escape of inflating fluid from the cuff.
 6. Theapparatus of claim 2, further comprising: a first coupler provided on anouter end of the outer cannula, a second coupler provided on an outerend of each inner cannula of the plurality of inner cannulas, whereinone of the first and second couplers including at least one surface forguiding the respective inner cannula into a use orientation with respectto the outer cannula when the inner cannula is inserted into the outercannula, and the other of the first and second couplers including acooperating surface for cooperating with the at least one surface forguiding the inner cannula into the use orientation with respect to theouter cannula.
 7. The apparatus of claim 2, wherein the plurality ofinner cannulas include a second inner cannula including a lumenextending therethrough, the second inner cannula being size to beinserted into the outer cannula in place of the first inner cannula.